1. Field of the Invention
This invention relates to a display device, and more particularly to an improved plasma display pane (PDP) for displaying a picture with the aid of a discharge caused by a radio frequency voltage signal. Also, this invention is directed to an improved driving method for the PDP.
2. Description of a Related Art
A conventional PDP brightens a fluorescent material by ultraviolet rays generated upon the gaseous discharge to display a picture including a character and graphic information. Then, the picture is displayed by visible rays emitted from the fluorescent material. The ultraviolet rays are emitted from gaseous particles when electrons included in the gaseous particles are excites and then transited, and are impacted to the fluorescent material. The gaseous discharge for generating such a glow discharge will be described.
A voltage signal is applied between a cathode 4 and an anode 6 installed into a discharge tube 2 as shown in FIG. 2. Then, an electrical field is formed in a discharging space between the cathode 4 and the anode 6, and electrons move from the cathode 4 toward the anode 6 in such a manner to be accelerated by the electrical field. The accelerated electron impacts into the gaseous particles, such as neutral atoms and molecules, injected in the discharging space to cause the ionization and excitation of gases. A variety pattern of luminescence appears at the glow discharge. Among the variety pattern of the luminescence, a negative glow generated in the vicinity of the cathode 4 and a positive column caused in the long region proceeding from the middle portion of the discharging space to the anode 6 affect to a brightness characteristics. Particularly, the positive column has a discharging efficiency of about 60-70 percents for the voltage that is applied between the cathode 4 and the anode 6. The positive column appears only in the case that the cathode 4 stands apart from the anode 6 above 1 mm. In other words, the electron must be moveable the long distance of above 1 mm. However, in the conventional PDP, a distance between two electrodes for receiving a discharge voltage is set below 150 xcexcm. Due to this, the conventional PDP must have used only the negative glow having the discharging efficiency of below 6 percents.
As PDP using such a negative glow, it is an alternative current type of PDP having plasma display cells as shown in FIGS. 2A and 2B. The plasma display cells are arranged in a matrix pattern. Referring to FIGS. 2A and 2B, the plasma display cell includes an upper substrate 10 and a lower substrate 12 installed apart from each other by compartment walls 14 in parallel. These upper and lower substrates and compartment walls 14 are formed a discharging space 26. The compartment walls 14 are formed by a material reasonable for preventing an optical interference and an electrical interference between the plasma display cells, and support the upper substrate 10. First and second sustain electrodes 16A and 16B, each called as a scan/sustain electrode and a sustain electrode, are installed on the upper substrate 10 in parallel with the compartment walls 14. On the upper substrate 10 with the first and second sustain electrodes 16A and 16B, a dielectric material layer 18 is formed to have an even surface. The dielectric material layer 18 stores up an electric charge. Also, a protective film 20 can be disposed on the first dielectric material layer 18. The protective film 20 protects the first dielectric material layer 18 from a spattering of gaseous particles to extend the lifetime of the PDP and to enhance an emitting rate or second electrons. The protective film 20 frees the discharge characteristics of a fireproof metal from a variation. As the protective film 20, it is mainly used a Magnesium Oxide (MgO) film. The upper substrate 10 with the above structure is disposed on the compartment walls 14 in such a manner that the sustain electrodes 16A and 16B are opposite to the lower substrate 12. Meanwhile, the lower substrate 12 has an address electrode 22 installed in such a manner to cross with the sustain electrodes 16A and 16B. On the lower substrate 12 with the address electrode 22, there is disposed a fluorescent material layer 24. The fluorescent material saver 24 excites and then transits by vacuum ultraviolet rays generated upon a gaseous discharge. The fluorescent material layer 24 emits visible rays having a primary color such as a red, a green or a blue color at a transition. The lower substrate 12 is positioned under the compartment walls 14 in such a manner that the address electrode 22 is opposite to the sustain electrodes 16A and 16B. These upper and lower substrates 10 and 12 and compartment walls 14 provide the discharging space 26 to be filled with discharge gases such as He, Ne, Xe and so on.
In the plasma display cell with such a structure, the sustain electrodes 16A and 16B stand apart from each other about 60-80 xcexcm. The compartment walls 14 are formed to be below 200 xcexcm in the height. In other words, all the distances between the electrodes 16A, 16B and 22 included in the plasma display cell is below 200 xcexcm. Due to this, the alternative current type of the PDP can not use the positive column. Consequently, the discharging efficiency of the PDP drops off. Also, the alternative current type of the PDP causes a address discharge between any one of the sustain electrode 16A and 16B and the address electrode 22 before a display discharge (or a sustained discharge) is generated between the first and second sustain electrodes 16A and 16B, thereby displaying a desired picture.
In the next, the PDP having the above structure will be described. The address discharge is generated by any one of the sustain electrodes 16A and 16B and the address electrode 22 and then the sustain discharge is continuously caused by the sustain electrodes 16A and 16B. The vacuum ultraviolet rays generating by the sustain discharge excite and transit the fluorescent material layer 24 to emit visible rays, thereby displaying a desired picture. The visible rays are generated when the fluorescent material layer 24 is transited. In other words, the alternative current type of the PDP displays a desired picture by the sustain discharge. In order to generate the sustain discharge, a sustain pulse is applied between the sustain electrodes 16A and 16B. The sustain pulse has a frequency of about 200-300 kHz and a width of about 2-3 xcexcm, as shown in FIG. 3. Responding to the sustain pulse, the sustain discharge causes only once at the shorter moment of the period of the sustain pulse. In other words, the greater part of the period of the sustain pulse is consumed regardless of real discharge.
For example, if the sustain pulse is applied to the first sustain electrode 16A, a charged particle moves from the second sustain electrode 16B having an opposing polarity toward the first sustain electrode 16A along a discharge path, as shown in FIG. 4. Then, the gaseous particles are excited and transited by the charged particle. As a result, the sustain discharge is generated in vicinity or the second sustain electrode 16B when a predetermined time have passed since the raising edge or the sustain pulse. Also, the charged particles from the electrode 16B opposite to the first electrode 16A are stored on the dielectric material layer 18 surrounding the surfaces of the sustain electrodes 16A and 16B. In other words, a wall charge is formed on the dielectric material layer 18 when the predetermined time have passed since the sustain discharge have been started. The wall charge offsets the voltage applied between the sustain electrodes 16A and 16B to drop down a voltage input to the discharging space, thereby reducing the sustain discharge. Consequently, the sustain discharge is generated only once during the shorter moment relative to the width of the sustain pulse.
As described above, in the PDP with the plasma display cell as shown FIGS. 2A and 2B, the positive column can not be caused because the distances of the electrodes are very shorter. Due to this, the discharging efficiency of the PDP decreases. Also, since the wall charge is formed at the sustain discharge, the discharge generates only once in a moment. For re-discharge, a predetermined period is required to eliminate the wall charge. Due to this, in the PDP with the plasma display cell, the period of the real discharge is very shorter than a period set up for the discharge, and the discharging efficiency decreases more. Consequently, the PDP with the plasma display cell as shown in FIGS. 2A and 2B can not provide with a sufficient brightness. Furthermore, the PDP requires an additional signal for eliminating the wall charge.
Accordingly, it is an object of the present invention to provide a plasma display panel that is adapted to obtain a sufficient brightness as well as to enhance a discharging efficiency, and a driving method thereof.
In order to achieve these and other objects of the invention, according to one aspect of the present invention there is provided with a plasma display panel comprising at least a pair of electrodes for applying a radio frequency voltage.
According to another aspect of the present invention, there is provided with a plasma display panel including: first electrode for applying a radio frequency voltage; second electrode for supplying a video data voltage; and a discharging space implemented with gas causing a gaseous discharge.
According to still another aspect of the present invention, there is provided with a plasma display panel driving method applying a radio frequency voltage into a discharge cell through at least a pair of electrodes to cause a display discharge.
According to still another aspect of the present invention, there is provided with a plasma display panel driving method including the steps of: applying a radio frequency voltage to a first electrode to starting simultaneously the discharge of cells; supplying a second electrode with a erasing pulse in accordance with a video data to stop selectively the discharge of the cells; and feeding a radio frequency voltage to the first electrode to maintain the discharge of the cells.
According to still another aspect of the present invention, there is provided with a plasma display panel driving method including the steps of: applying a first electrode with a driving signal corresponding too a video data to select discharge cells; and supplying a radio frequency voltage to a second electrode to generated continuously a display discharges in the discharge cell selected by the driving signal.
According to still another aspect of the present invention, there is provided with a plasma display panel driving method including steps of: applying a first electrode with a driving signal corresponding to a video data to allow charged particles to be selectively injected into discharge cells; supplying a sustain voltage to additional electrodes to preserve the charged particles; and feeding a radio frequency voltage to a second electrode to generate continuously a display discharge by the charged particles.